This invention concerns a method and apparatus for applying lubricant to railroad rails. Rail lubrication on curves has been considered important for a long time, primarily for the purpose of reducing wear on wheels and rails. Traditionally, lubricating devices in railroad yards used long bars mounted on the gage side of the rail. Grease oozes out of small holes in the bar in response to the pressure of a passing train, and is picked up by the flanges of wheels and spread over the rail gage corner. These grease lubricators are difficult to control, leading to excessive grease being applied and accumulated near the applicator. It is messy, manpower intensive, hazardous to track crews, and expensive to maintain. In spite of such lubrication, high lateral forces continue to develop on the rail. This produces significant damage to track components such as spikes, ties, tie plates, ballast and the overall structure of the track.
A new approach called top-of-rail lubrication was introduced by Kumar in the early 1990s. See U.S. Pat. Nos. 5,477,941 and 5,896,947. In this approach, a lubrication system mounted on the last locomotive consistently applied lubricant or friction modifier on top of the rail as the train moved forward. This approach has been very beneficial, and today the railroad industry generally utilizes the top-of-rail method of lubrication. Since this system is installed on board a locomotive, it falls under the authority of the mechanical department in a railroad.
The engineering department of a railroad also needs a system for top-of-rail lubrication on curves. Recently, two different systems have been developed for achieving this. One system follows the approach similar to gage side grease lubricators. In this approach a long bar is installed on the field side and top of the rail. When wheels pass by, the pressure causes the lubricant to ooze out of the strip to be spread on the rail. This is not effective because it does not provide lubrication where it is needed most, particularly on the low rail in a curve. Also, the lubricant is not carried along the track for a sufficient distance.
There is a second approach called the wayside wheel lubricator which is currently at work in many railroad yards. This is shown in Kumar, U.S. Pat. No. 6,585,085, assigned to Tranergy Corporation. In this method, lubricant is applied through a nozzle to the wheels of approaching cars in a yard which move at relatively slow speeds (10 miles per hour or less). While this method is effective in railroad yards, for cars traveling at higher speeds (40 to 70 miles per hour) the lubricant application jet will have difficulty accurately hitting fast approaching wheels. There is therefore a great need for a ground-based, top-of-rail lubrication system which lubricates the contact area of the rail using an optimum amount of lubricant on the optimum area of the railhead.